EXTENDED FORECAST DISCUSSION NWS WEATHER PREDICTION CENTER COLLEGE PARK MD 834 PM EST SUN FEB 12 2017 VALID 12Z THU FEB 16 2017 - 12Z MON FEB 20 2017 ...WIDESPREAD PRECIPITATION FOR THE WEST, SOUTHERN/CENTRAL PLAINS, AND FLORIDA... OVERVIEW ~~~~~~~~ AN ACTIVE PATTERN SHOULD CONTINUE FOR MUCH OF THE LOWER 48, PRIMARILY FOR THE WEST AND THE SOUTHEAST. UPPER RIDGING INITIALLY OVER ALBERTA IS FORECAST TO SLIDE SOUTHEASTWARD TOWARD THE GREAT LAKES BY NEXT WEEKEND WHILE TROUGHING TO ITS EAST WHIPS THROUGH THE NORTHEAST INTO ATLANTIC CANADA. IN THE PACIFIC, A STRONG JET BETWEEN ALASKA AND HAWAI'I SHOULD FORCE TROUGHING INTO THE WEST/MEXICO LATER IN THE WEEK WHICH WILL BRING IN WIDESPREAD RAINFALL TO CALIFORNIA. TO THE EAST, A LEAD UPPER LOW WILL SLOWLY BUT STEADILY LIFT OUT OF NORTHERN MEXICO AND THEN MOVE THROUGH SE TX/LOWER MS VALLEY/SOUTHEAST THROUGH NEXT WEEKEND. GUIDANCE EVALUATION ~~~~~~~~~~~~~~~~~ DIFFERENCES ACROSS THE LOWER 48 ARE DOWN TO THE NOISE LEVEL, MEANING A COMPROMISE OF THE 12Z UKMET, 12Z CANADIAN, 18Z GFS, 12Z ECMWF, THE 12Z ECMWF ENSEMBLE MEAN, AND THE 12Z NAEFS MEAN WERE USED FOR THE LOWER 48 GRIDS THROUGH THE PERIOD. THE DAYS 4-7 HAVE BEEN BASED ON A ROUGH COMPROMISE OF THE 12Z ECMWF AND 18Z GFS, AND MAY INCLUDE THE 00Z GFS IF ITS SOLUTION IS WITHIN THE REALM OF POSSIBILITY. ACROSS THE SOUTHEAST WITH THE INITIAL UPPER LOW EJECTING OUT OF THE SOUTHWEST, TRENDS HAVE BEEN IN THE DIRECTION OF THE ECMWF SINCE THIS TIME YESTERDAY, WHICH HAS LED TO A QUICKER RETURN OF MOISTURE AND PRECIPITATION TO THE SOUTHEAST THAN ANTICIPATED THIS TIME YESTERDAY. WEATHER HIGHLIGHTS/THREATS ~~~~~~~~~~~~~~~~~~~~~~~~~~ A POTENTIALLY ROBUST NOR'EASTER ON WEDNESDAY/THURSDAY SHOULD BE MOVING OUT TO SEA AND INTO ATLANTIC CANADA EARLY ON, WITH NW FLOW BEHIND IT OVER THE EASTERN LAKES (MODEST LAKE EFFECT SNOW) INTO THE CENTRAL APPALACHIANS. TEMPERATURES SHOULD REBOUND BY FRIDAY IN THE NORTHEAST AS THE NOR'EASTER PULLS FARTHER AWAY. INCREASINGLY WIDESPREAD PRECIPITATION SPREADS ACROSS THE WEST FROM NORTHERN CA NORTHWARD ACROSS OR AND WA, EVENTUALLY EXTENDING INLAND INTO THE NORTHERN ROCKIES AND TERRAIN IN AND NEAR THE GREAT BASIN, SOUTHWEST, AND CENTRAL ROCKIES. BY FRIDAY INTO THE WEEKEND, ENSEMBLES SUPPORT A WIDESPREAD MODEST RAIN EVENT FOR SOUTHERN CALIFORNIA AS HEIGHTS DIG INTO NW MEXICO. AS THE SYSTEM MOVES TOWARDS THE SOUTHERN PLAINS, HEAVY RAINS APPEAR TO BE IN THE CARDS FOR TX/LA ONCE MORE SUNDAY INTO MONDAY. THE NORTHERN PLAINS, UPPER MS VALLEY, GREAT LAKES, AND EVENTUALLY NORTHEAST SHOULD SEE ABOVE NORMAL TEMPERATURES AS A LARGE AND ROBUST POSITIVE MID-LEVEL ANOMALY SPREADS ACROSS THE REGION. COOLING MOVES INTO THE WEST, IN CONCERT WITH THE PROGRESSION OF THE DEEP LAYERED TROUGH. AS HEIGHTS BUILD INTO THE HIGH PLAINS AND UPPER MIDWEST NEXT WEEKEND, TEMPERATURES SHOULD RISE TO 10-20F ABOVE AVERAGE (60S TO THE SD/MN LINE). RECORD HIGHS ARE POSSIBLE IN THE CENTRAL STATES NEXT WEEKEND WITH MOST OF THE CENTRAL/EAST ABOVE FREEZING EVEN OVERNIGHT. ROTH/FRACASSO